[R] Reading Version 4 .sdd files
Prof Brian Ripley
ripley at stats.ox.ac.uk
Mon Oct 4 21:05:07 CEST 2004
On Mon, 4 Oct 2004, John Chandler wrote:
> Dear R-Help,
> I've never had any trouble importing data into R until I had to import
> an .sdd file for a class. The file can be found here:
> http://www.math.umt.edu/steele/Math%20549/Farms.sdd. It begins with the
> line "## Dump S Version 4 Dump ##". I first attempted read.S which
> issued the message "not an S object". I then checked the Import/Export
> manual which seemed to indicate that data.restore might do the trick.
That manual says otherwise.
> Alas, it seems that function is trying to interpret the name of the data
> frame as an S mode or some such thing.
> Searched the archives (courtesy of Dr. Baron) and found this from Dr.
> Ripley: ".sdd files from S-PLUS 6.0 are
> S4 dumps, and will not work." This was written in 2002, is it still
Yes. It's right there on the help page for data.restore, twice! It is
also in the `R Data Import/Export Manual' you cited.
> Right now my only obvious course of action is to get on a
> machine that has S+, read in this file and dump it in a more useful
> format. Are their others?
Not that I have ever heard of, at least not open to those who have no
access to S4 source code. Whereas the S3 dump format has been disclosed,
I don't believe that the S4 one has.
If this is an S4 class then you really want a dump of it, as R's internal
representation is not at all like S4's, I believe.
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
More information about the R-help